Incandescent lamp.



F. M. DORSEY & H. D. BLAKE.

INCANDESCENT LAMP. APPLICATION FILED FEB. 5. 1914.

1,250,815. Patented 1).... 18, 1am

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- Inventor's Witnesses: Frank TT'LDorseg,

MW Wake. b Q M W T eirdlttorne g.

. UNITED sTATEsrATENT OFFICE.

FRANK M. DORSEY AND HAROLD D. BLAKE, OF CLEVELAND, OHIO, ASSIGNOBS TOGENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

INCANDESOENT LAMP.

Be it known that we, FRANK M. DORSEY land HAROLD D." BLAKE, citizens "ofthe \f United States, residing at Cleveland, in the county of Cuyahoga,Stateof Ohio, have invented certaln new and useful Improvements inIncandescent Lamps, of which the following is a, specification.

Our invention relates to incandescent lamps in Which the filament iscomposed of tungsten .or like metal. More specifically, our inventionrelates to means for maintaining the candle power and increasing theefliciencyof lamps of this character. Varione chemicals known as gettershave been To all whom it may concern:

laced in the bulbs of incandescent lamps or this purpose. Our inventioncomprises a new getter having many advantages, as will appear from thedetailed description which follows. We have found that phosphorus in thesolid form associated with, 'a substance which will readily give upoxygen to phosphorus at the operating temperature of the lamp is veryeffective in increasing the elliciency of metal filament. lamps. Certainmetallic oxids such as cupric oxid we have found to be especiallyadapted for use in this connection. As to the chemical action 8d whichtakes place when a mixture of this kind is used in an incandescent lamp,it may be that at the operating temperature of the lamp the phosphoruscombines with a ortion of the cupric oxid to form an oxi or oxids ofphosphorus and cuprous oxid. However, we do not wish to be confined toany. particular theory of operation. Certain oxids of phosphorus, forexample, phosphoric pentoxid, have considerable affinity for water vaporand the vapors given off during the life of the lamp. This action wouldbe highly effective in maintaining the candle power of the lamp, sinceit would obviate the injurious effect of water vapor and at-the sametime combine with and neutralize to a considerable 'extent the efllectof any vaporized metal or metallic compounds which might be developed inthe bulb. Another aspect of our invention is that a compositionembodying our inventionnnay be used in connection with incandescentlamps which have copper filament supporting; hooks. With the getterswhich have been heretofore proposed it has been found desirable to usemetals other than copper for Specification of Letters Patent.

Application filed February 5, 1914. Serial No. 816,668.

supporting hooks, because of the chemical action between these gettersand the cop- 7 per or copper oxid with which copper hooks usually becomecovered during the manufacture of the lamp. Copper is a very desirablemetal to, use in connection with metal filaments, such as tungsten,because of the fact that the'copper does not alloy with the tungsten andit is fairly cheap metal and can be easily worked. It is to beunderstood, however, that the composition comprising our invention isapplicable also to lamps in which the filament supporting hooks arecomposed of other metals. In fact, exceptionally good results have beenobtained with tungsten hooks.

One method which we have found eflicacious in preparing our getter is tomix 100 ,parts, by weight, of cupric oxid, 2% to 5 parts, by weight, ofred phosphorus, and enough sodium silicate solution of specific gravity,1.09 to 1.15, to form a suitable paste. n mixing it is very desirable,in order to obtain a uniform intermingling of the constituents, to firstmix the phosphorus with the binder and to then add the cupric oxid. Thecupric oxid should be free from salts such as sulfates and chloridswhich are apt to be present in the ordinary commercial variety.

Instead of mixing the phosphorus and oxidizing agent such as copperoxid, the lat- .ter only with a binder may be placed in the lamp andphosphorus added by volatilizing it into the bulb in the mannerdisclosed in Malignani Patent No. 537,693, April 16, 1895. However, thisprocedure, while giving good results, is not considered to be as good asthe direct'mixing of the phosphorus and oxidizing agent. 1

In the drawing is shown one way in which our invention may be applied toincandescent lamps. Figure 1 is an elevation partly broken away of suchan incandescent lamp, and Fig. 2 is a detailed view, on an enlargedscale of one of the supporting hooks with the getter in place.

The lumps of getter 10 are ap lied to the hooks 12, which support theament 11. The hook serves to anchor the lump of getter securely inplace. Owing to the fact that the getter is thus brought in closethermal contact with the filament, it is efiectively heated during suchtime as the lamp is in use. By mounting a small lump of the getter oneach of the supporting hooks an effective distribution throughout thebulb is obtained. By thus subdividing the material the results securedare much better than if the material were concentrated at a single oronly a few points. However, it is to be understood that it is notessential to our in vention that the getter be mounted in any particularway. p

The sodium silicate hereinbefore referred to acts as a binder to holdthe copper oxid and phosphorus mixture together and probably has nochemical action. 1

What we claim as new and desire to secure by Letters Patent of theUnited States, is

1. An electric incandescent lamp comprising a bulb, a metallic filamentand a getter comprising phosphorus and anon-gaseous oxidizing agentwithin said bulb.

2. An electric incandescent lamp comprising a bulb, a tungsten filamentand a getter 5. An electric incandescent lamp comprisv mg a bulb, atungsten filament and a getter comprising phosphorus and" cupric oxidwithin the said bulb.

In witness whereof, we have hereunto set our hands this 2nd day ofFebruary, 1914. FRANK M. DORSEY. HAROLD D. BLAKE. Witnesses J. H.ANDERSON, CHAS. E. STROBEL.

